Panelboard with insulative circuit breaker supports mounted on the bus bars

ABSTRACT

A panelboard comprises an elongated bus bar having insulating breaker support means supported on the bus bar and a plurality of circuit breakers supported in a column with each breaker supported at one end thereof on the insulating breaker support means. The panelboard comprises a stationary part and a movable cover with an improved concealed hinge movably supporting the cover on the stationary part.

United States Patent [72] Inventors Robert G. Anderson;

7 References Cited William M- DOllflid; Tony J. Drag, 81] 0 UNITEDSTATES PATENTS Ontario, Canada 808,872 8/1966 3.267.336 317/1203,375,411 3/1968 Mrowka......U...........l... 317/119 [21] AppLNo [22]Filed Mar-20,1969

FOREIGN PATENTS 694,619 7/1953 Great Britain.... 880,552 10/1961 PrimaryExaminer-Lewis H. Myers [45] Patented June 29, 1971 [73] AssigneeCanadian Westinghouse Company, Limited Hamilton, Ontario, Canada GreatBritain...............'.

Assistant Examiner-Gerald P. Tolin 54 PANELBOARD WITH INSULATIVE CIRCUITAu0rrieys--A. T. Shanon, C. L. Mcl-lale and w. A. Elchik BREAKERSUPPORTS MOUNTED ON THE BUS BARS ABSTRACT: A panelboard comprises anelongated bus bar Chums 9 Drawing Figs having insulating breaker supportmeans supported on the bus 317/119, bar and a plurality of circuitbreakers supported in a column 16/164, 49/398, 317/120 with each breakersupported at one end thereof on the insulat- Int. 1102!) 1/04 ingbreaker support means. The panelboard comprises a sta- [50] Field of49/398, tionary part and a movable cover with an improved concealed 7hinge movably supporting the cover on the stationary part.

PATENTED JUN29 IBYI SHEET 1 OF 4 PATENTEB JUN29 an SHEET 2 BF 4 FIG. 3.

PATENTEU JUNZS l9?! SHEET BF 4 PANELBOARD WITH INSULATIVECIRCUIT BREAKERSUPPORTS MOUNTED ON THE BUS BARS This application relates to an improvedlighting and distribution panelboard which incorporates features whichlead to greater flexibility in ultimate use because of the ability to beadapted to receive various circuit breaker assemblies without requiringsubstantial alteration. The bus bar structure which is of a simple andrugged construction is readily mountable in a protective enclosure andby making various minor adaptions to the bus bar structure, it ispossible to provide an assembly which will receive circuit breakers ofvarious ratings. It is also necessary, at the same time, to provide busbar assembly which is capable of dissipating heat in accordance withcertain standards as set out by regulatory bodies. The novelconstruction of this panelboard assembly is such as to allow foradequate convection and conduction of heat from the assembly, which heatis generated in all current carrying members of the assembly so that thetemperature of all of the current carrying members of the panelboardremain well within the statutory limits.

The panelboard assembly comprises insulating bus bar support means andthree elongated bus bars supported on the bus bar support means in agenerally parallel relationship. An elongated insulating breaker supportmember is supported on each of the outer bus bars. A plurality ofcircuit breakers are supported on the panelboard in two columns. in eachcolumn each circuit breaker is supported at one end thereof on theassociated insulating breaker support means. Each of the insulatingbreaker support means comprises a shelf portion that the associatedbreakers rest on and a separate hook part for each of the breakers witheach hook part interengaging with a different one of the breakers.

The panelboard assembly has provision for an entirely new trim memberwhich is attached in a new and different manner to the main body of thepanelboard assembly. The trim panel member also functions as the mainsupport for the door which ordinarily provides access to the circuitbreaker handle mechanisms in the panelboard, and provision has been madeto swing the door 180 from its closed position by use of a concealedhinge.

1n the design of distribution panelboards, several importantconsiderations must be kept in view during the design of suchstructures. Firstly, of course, the panelboard must be both structurallyand electrically safe. This means that the material comprising the outershell of a panelboard must conform to specific regulations and be of acertain grade and gauge of a material in keeping with the regulations,and be of such particular configuration as to provide sufficientstrength to resist collapse by impact or prevent intrusion by foreignobjects, accidental or otherwise. At the same time, adequate clearancesmust be maintained between the electrical current carrying members whichare of different electrical potentials and simultaneously provision mustbe made for the dissipation of heat for any current carrying members. Itis quite easily seen that all the above restrictions cause the design ofthe panelboard to be quite standard, and in the past most panelboarddesigns have been quite similar.

More and more pressure is being brought upon the panelboard designer toprovide a panelboard assembly which will easily adapt to receive circuitbreakers of various ratings and architects are specifying panelboardassemblies which will present smooth uninterrupted exposed faces forlocations where the panelboard assembly must be acceptableaesthetically.

This panelboard is able to accomplish the above objectives by providinga bus bar structure which is quickly and easily mounted in the main bodyof the panelboard assembly by means of a pair of phenolic end pieces towhich is attached the bus bar structure. The bus bar structure isattached to the main body of the panelboard assembly by means of fourmounting bolts. A trim cover which is provided to cover the exposedcircuit breaker assemblies is fastened to the panelboard body by meansof four additional mounting bolts. A door which is actually a part ofthe trim cover member is held to the trim member by a concealed hingewhich is of a special design to allow the door to swing in the closedposition. The exposed portion of the panelboard assembly is made so asto form a smooth continuous uninterrupted face with the onlydiscontinuity being the handle which is used to operate the concealedlatch in the door assembly. A further elucidation of the invention willbe found with the aid of the accompanying drawings, in which:

FIG. 1 is an exploded view of the panelboard assembly, showing the maincomponents necessary for an understanding of the invention.

HO. 2 is an enlarged exploded view having partial sections in some ofthe components of the main bus bar structure of an assembly whichutilizes circuit breakers of a relatively low ratmg.

FIG. 3 is a view of the interior of the panelboard showing theconnection of bolt on circuit breakers which are being energized fromone of the two outside bus bars.

FIG. 41 is a view of the interior of the panelboard showing theconnection of a bolt on breaker which is being energized from the centerbus bar.

FIG. 5 is a view of the interior of the panelboard which shows a "bolton circuit breaker being energized from the opposite exterior bus bar tothat being shown in FIG. 3.

F IG. 6 is a partial sectional projection showing the hinge assemblywhich permits the door to swing 180 from the closed position.

FIG. 7 is an enlarged plan view of the hinge assembly showing the doorin the both open and closed position.

FIG. 8 shows the interior elements of the panelboard assembly which isnecessary for the adaption of the panelboard assembly in order toreceive circuit breakers of a much larger rating than those which havebeen shown previously.

FIG. 9 is a view of the panelboard assembly when it is desired toprotect the entire bus bar structure with a single circuit breaker,which is included in the panelboard assembly.

Referring now to FIG. 1, a rectangular boxlike structure, 10 is shownwhich is the main body of the panelboard assembly. Member 10 is composedof sheet steel of a particular gauge, and has a turned over flangeportion 11 on the forward face thereof. .The front face of member 10 isotherwise completely open in order to receive a bus bar structure.

Four mounting posts 12, 13, 14 and 15 are attached to the rear of thepanel member 10 by any convenient means. It is envisioned that theattachment of the four mounting posts will be by bolts or welding, orany other suitable means. Each of the posts 12, 13, 14 and 15 isprovided with a tapped hole in the forward facing end of the post.

There are also four stamped out portions in the rear face of thepanelboard body 10, which are shown as 17, 18, 19 and 20. The stampedout portions 17, 18, 19 and 20 are provided for the attachment of thebolts which are used to subsequently fasten the bus bar assembly to themain body 10. Only one of the bolts is shown, but it is obvious that itis necessary to have four such bolts as shown as 21 in order to fastenthe assembly to the main body 1111. Bolt 21 is provided with a flatelongated head so that it may be accepted in the stamped out area 17 ofthe body 10, and will be restrained from twisting when installed instamped out portion 17. Bolt 21 is secured in stamped out area 17 by nutmember 22 which is tightened securely against the forward face of thestamped out area '17. Also fitted on bolt 21 is an adjustable nut member23. Nut member 23 is provided a specially shaped exterior contour inorder to be easily adjusted by the fingers of the person installing thepanelboard. Nut 23 acts as a spacer on bolt 21 to provide a stop for thebus bar assembly in order to provide the necessary clearance between thebus bar assembly and the rear face of the body 10.

The bus bar assembly 30 is shown having two phenolic end pieces 33 and34, which are fastened together by three bus bars, 35, 36 and 37. Thebus bars are bolted to the phenolic 33. it will be seen that each busbar is manufactured with a series of two tapped holes passing througheach bar at spaced vertical intervals. lnthe assembly of this structure,it is necessary that each set of tapped holes 'in the three bus bars bein the. same horizontal plane. The bus bars may be composed of eitheraluminum or copper, whichever is most convenient. It is also seen thatbus bar 36 is in a different vertical plane than the bus bars 37 and 35.The reason for this will appear obvious later on in the disclosure. Thebus bar assembly 30 is attached to the main body member by the passageof four bolts such as that shown as 21 through holes shown as 31 forbolt 21. The phenolic end piece 33 is adjusted against stop nut 23 untilthe desired clearance is obtained between the bus bars 35, 36, 37 andthe rear face of body member 10. The two phenolic end pieces 33 and 34are then secured tightly against the adjustable stop nuts similar tothat shown as'23 by means of four wing nuts, one of which is shown as32.

it will be noted that bus bar 37 is attached to end piece 30 by means ofa bolt 40 which passes through cable clamp 41 so as to secure the busbar 37 to the phenolic end piece 30, while simultaneously attachingclamp 41 to bus bar 37 to ensure good contact between the cable clampand the bus bar 37. The shaping of the phenolic end pieces is veryimportant in that portions shown as 42 and 43 are cut out centralportions in the dropped center section of each phenolic end piece. Thisshaping allows for dissipation of heat by changing the position of thecenter bus bar 36 and allows for convection to increase the dissipationof heat in the bus bar assembly. The phenolic end pieces are alsoprovided with additional holes, only two of which will be described,thesebeing 44 and 45, which are used for the attachment of the neutralbus assembly 46 by means of bolts 47 and 48, which are passed throughholes 44 and 45 and are tapped into the neutral bus assembly block 49.Block 49 also serves as a cable clamp for the neutral cable connectionto the neutral bus assembly. I

Similarly, end piece 50 is bolted to the left-hand side of end piece 33.This secures the neutral-bus assembly 46 in a position at thetop of thebus bar structure 30. It is noted that end The trim panel 80 actually iscomposed of two pieces, .the stationary portion which is fastenedto mainbody member 10 which is composed of a forward facing sheet metal portion81 to which is spot welded or joined by any other suitable means asecond portion 82, which is formed by stamping out, or some othersuitable metal forming operation to provide the contour as shown in thebroken away section at the top of the panel assembly 80 labeled A. Adoor, 83, which is shown in partial cutaway view is also attached to thestationary trim portion by a pair of special hinges which will bedescribed later. Member 82 has two punched out portions shown as 84 and85, which are necessary for access to the operating handles of thecircuit breakers when the trim member 80 has been installed byattachment to body member 10.

The attachment of the trim member 80 to the body member 10 is by meansof four bolts similar to that shown as 86, passing through four holessimilar to that shown as 87 in member 82 and subsequently are threadedinto the posts which are shown as 12, 13, 14 and '15. The four boltssimilar to 86 provide a quick, speedy and rigid attachment for the trimmember 80 to the body member 10, and yet provide no visible indicationsfrom the exterior of the method of attachment of the trim member 80 tothe body member 10, when the trim member is finallyattached and the dooris closed.

Reference will now be made to FIG. 2, which shows the attachment ofcircuit breakers of two dissimilar types to the bus bar structure. Theattachment of a bolt on" circuit breaker to the bus bar assembly will bedescribed first. The bus bars 35, 36, 37 are shown in partial section inthis view and are in the same spaced relationship as shown in FIG. 1,that is, bus bar 36 is physically located a small distance behind theplane piece is a sheetmetal member which is made so that the neutral busassembly 46 will easily pass through the slot provided in end piece 50for rapidattachment thereto.

The general construction of the circuit breaker assemblies and themethod of attachment to the bus bar structure will now be described. Theassembly necessary-for the attachment of the circuit breaker assembliesto the bus bar structure is generally labeled 70. This includes asegmented insulator 71 which is composed of bakelite, heat resistantplastic or some other suitable insulating material which is shaped insuch a manner that the rear portion is channelled out to provide a loosesliding fit over the bus bar 36. The insulator is segmented on thefront, having horizontal channels (as opposed to the vertical channel onthe rear portion) so as to separate the forward facing portion of theinsulator 71 into various segmented areas. An insulated circuit breakerreceiving member 72 is shown havingholes provided which are aligned withthe holes provided in the bus bar 35, this being to facilitate theattachment of bus bar receiving member 72 to the bus bar 35 by screws. Abus-adapter 73 is provided to be electrically connected to bus bar 35and carry current to one segment of insulator 71, preferably the top asshown in FIG. 1. The second bus adapter member 74 is provided to beattached to bus bar 37 and to conduct electrical currents into one ofthe forward segments of insulator 71, preferably the lower segment asshown in FIG. 1. Electrical spacers 75 and 76 are made of electricallyconductive material and are suitably received in the rear portion ofinsulator 71, in a recess behind the front center segment shown ininsulator 71.

The circuit breaker shown as 77 may then be connected to any one of thesegments merely by fastening one end of circuit breaker to the receivingmember 72 and by bolting the opposite end to the appropriate segment ofinsulator 71. The actual installation will be described in detail later.

passing through bus bars35 and 37. As stated previously, all the busbars are provided with a series of carefully spaced, tapped holespassingcompletely through the bus bar. It is noted that each bus bar isprovided with two holes located in the same horizontal plane and spacedequidistantly from the center of each bus bar.

A circuit breaker attachment member 72 is shown bolted to bus bar 35 bymeans of bolts and 102. Member 72 is an electrically insulatingmemberwhich may be composed of heat resistant plastic, insulated sheetsteel or any other suitable material which will conform with safetyregulations. Member 72 is provided with a stamped out hook portion 112which is necessary to attach the circuit'breaker into the bus barassembly. It is noted that not all the tapped holes in bus bar 35 on theleft-hand side are required for the attachment of member 72. However,for manufacturing ease, it is generally easier to provide a pair ofholes at'regularly spaced intervals regardless of whether or not theholes will be used in the ultimate assembly of the structure.

Also attached to bus bar 35 adjacent bolt 100 is a bus adapter 103 whichis electrically connected to bus bar 35 by bolt 104. Member 103 may bealuminum or copper or any other suitable electrical conductor, andmember 103 is necessary to carry current from bus bar 35 to the topmostsegment 107 of insulator 71 shown abutting bus bar 36.

Connected to bus bar 37 is a circuit breaker receiving member 105 whichis identical with that shown as 72. Member 105 is shown connected to busbar 37 by means of bolt 106, and has a hooked out portion 122 necessaryfor receiving circuit breaker 120. Insulator 71 which has a channelledout section at the rear portion thereof is madeto fit neatly'over busbar 36 and provision is made to attach insulator 71 in place to bus bar36 while providing three different electrical potentials to the threeforward separated segments of insulator 71.

Segment 107 of insulator 71 is arranged to be energized from bus bar 35by means of bus adapter 103. Because bus bar 36 is set back in avertical plane behind bus bars 35 and 37 by an amount equal to thethickness of insulator 71 in the segment 107, the bus adapter will fitsquarely upon the face provided in segment 107. Segment 108 is providedwith two apertures so that conductive spacers 75 and 76 may passentirely segment 108. Conductive spacers 75 and 76 have a pair of arelarger than the aperture provided in segment 108 for the passage of theforward portions of spacers 75 and 76.

In order to connect a .bolt on circuit breaker into the assemblyprovided, the circuit breaker 110 which is provided with a standardrecess 111 is hooked over hook 112 in bus bar receiving member 72, and asuitable bolt is passed through hole 113 of the energizing terminal ofcircuit breaker 110, and through a suitable clearance hole in busadapter 103; into tapped hole 114 in insulator segment 107. The boltused to attach circuit breaker 111) to insulator 71 must be short enoughto fit in hole 114 which, ofnecessity, must be a blind hole so as not tocontact bus bar 36. it is thus seen that circuit breaker 110 is nowbeing energized from bus bar 35 and is completely insulated from bus bar36. If it were desired to energize circuit breaker 110 from bus bar 36,the circuit breaker would be hooked to the hook in circuit breakerreceiving member 72 directly below that shown as 112, and a bolt wouldbe passed through hole 113, through the hole provided in spacer 76, andthreaded into the tapped hole provided on the left-hand side of bus bar36, located immediately behind conductive spacer 76.

This method of fastening has two advantages. Because of the forward faceof spacer 76 passing completely through the insulator 71, a suitableconductive area is established between spacer 76 and circuit breaker110, which keeps the heat generated at the junction of circuit breaker110, and spacer 76 to a minimum. Also when the bolt is passed throughthe clearance hole provided in spacer 76, spacer 76 is then permanentlylocated on and secured firmly to bus bar 36. This serves as a means ofindexing insulator 71 with respect to the tapped holes in bus bar 36.The aperture made in segment 108 for the passage of conductive spacers75 and 76 may be quite loose in order to facilitate assembly of theentire structure, however, the clearance is not critical.

Segment 109 is arranged to be energized by electrical energy from busbar 37. A bus adapter member 115 which is similar in all respects tothat shown as 103 is bolted by means of bolt 116 to member 37 in thetapped hole provided. Member 115 is arranged to have two holes in theend opposite the end attached to bus bar 37 so that a pair of bolts 118and member 117, which is 11) may be used to secure the preferably calleda stab connector and bus adapter 115 in good conducting relationship.Bolts 118 and 11? pass through clearance holes in stab connector" 117and through clearance holes in bus adapter 115 and into two tapped blindholes in insulator 71, similar to those shown in segment 107, one ofwhich is labeled 114. The bus adapter 115 and stab connector" 117 andinsulator 71 are rigidly coupled together to form a complete unit. Forthe connection of a stab on" circuit breaker, shown here as 120, it isnecessary to pass recess 121 over hook 122provided in member 105. Thecircuit breaker 120 is then pivoted about hook 122 in order to forcestab connector" 117 into spring loaded recess 123. This type of circuitbreaker is quite standard, and the construction provides adequateassurance that suitable contact will be made with stab connector 117 bythe electrical conductors which are spring loaded to recess 123.

FIG. 3 is a partial sectional view showing the general connectionsnecessary for the energization of a pair of circuit breakers from one ofthe outside bus bars. The circuit breakers 133 and 135 are shownenergized from bus bar 35, which is shown having bus adapter 103connected by bolt 104 into the bus bar 35. The cross-sectional view ofone of the seg ments of insulator 71 such as 107, is provided to givethe reader a better understanding of the connection to bolt on" circuitbreakers with the associated bus adapter and insulator 71. it is notedthat the circuit breakers 133 and 135 are rigidly connected to insulator71 by means of the blind tapped holes provided in insulator 71 andsimultaneously good electrical connection is assured between theconnector portions of the circuit breakers such as is shown as 132 forcircuit breaker 113 and the bus adapter 103. it is noted that bolts 130and 131 are of such a length as to fall far short or'pnssing through theinsulator 71.

FIG. 4 provides a partial sectional view of the attachment of a circuitbreaker of the bolt on type when it is desired to energize the circuitbreaker from the center bus bar. The attachment to circuit breakerreceiving member 1115 to bus bar 37 is quite standard and will not bedescribed further. it is the connection between the energizing terminal143 of circuit breaker 1411 to the bus bar 36 which is of interest.Conductive spacer 76 is arranged so that the shoulder butts against thebus bar 36. Conductor 143 is arranged to have a clearance hole throughwhich is passed belt 142. Bolt 142 also passes through a clearance holein conductive spacer 76. Bolt 142 is threaded into the tapped hole inbus bar 36 and is tightened a sufiicient amount to ensure goodelectrical contact between the bus bar 36, the conductive spacer 76 andthe energizing terminal 143 of circuit breaker 140. As statedpreviously, it is through the arrangement of positioning the conductivespacers '75 and 76 in insulator 71 which indexes insulator 71 withrespect to the tapped holes in a bus bar 36.

Referring now to FIG. 5, circuit breaker 147 is shown being energizedfrom bus bar 37. in this instance, the bus adapter 151 is attached tobus bar 37 by bolt 152. The bus adapter 151 extends into a segment ofinsulator 71 such as N19 to provide the proper potential to thatparticular segment of insulator 71. Bolt 154 passes through energizingterminal 153 of the circuit breaker 147, and through bus adapter 151into the blind tapped hole provided in insulator 71. Similarly, theadjacent circuit breaker 148 is attached to bus adapter 151 by screw155.

it is thus seen that a series of breakers may be located in two columnsadjacent one another in this construction, and if the bus bar assemblyis energized by three phase alternating current as is quite common, thebreakers are energized in pairs in an orderly sequence from each ofthree phases.

insulator 71 may have as many segments as possible, or it may be amodular-type construction so that the basic module is composed of threesegments and any number of basic modules may be used in theconstruction. The same reasoning applies to the circuit breakerattaching devices shown as 72 and 105.

Referring now to H6. 6, wherein the hinge assembly is shown, it will benoted that the hinge assembly provided will permit the door to swingfrom the closed position, yet when in the closed position, the doorcovers the hinge ass'ernbly completely, thus giving no indication of ahinge while viewing the exposed face of the completed panel assembly.Stationary trim member 81 is shown in partial section, as is the formedmetal section 82 which is joined to trim portion 81. A U-shaped channelportion 184 is attached to the rear side of trim portion 81 by weldingor any other suitable method so that the bight of the U-shaped channel184 rests against the interior of the trim member 81. Similarly, anidentical U-shapcd channel member 185 is welded or joined by any othersuitable such a manner that the bight of the U-shaped channel section185 is attached rigidly to the interior of the door, as shown in FIG. 6.A hinge pin 1.86 is passed through two holes provided in the U-shapedchannel 184, and also through two similar holes in U-shaped channel 185to provide the required pivot for the door. It will be observed fromFIG. 7, that the central portion of the hinge pin is formed in such amanner as to provide the necessary clearance to eliminate anyinterference between the stationary trim member 81 and the door 33. 1tsill also be noted that when the door is closed, the hinge pin member186 and the two channels 184 and 185 are concealed.

FIG. 8 illustrates a circuit breaker of a much larger size than anypreviously illustrated is to be mounted into the bus bar structure. Thebus bar structure is very similar to that illustrated previously as 30in FIG. 1. However, because of the size of the breakers to be attachedto the bus bar structure, it is necessary to mount the entire assemblyon a steel backing plate, shown illustrated as 200. Member 2011 is asheet metal formed assembly which isprovidedfor the attachment of thephenolic end pieces, one of which is shown as 230. Member 200 has twooutside flange portions, 201 and 202, which have been drilled and tappedat predetermined spaced locations which will provide support for the endof the circuit breaker assembly remote from the center of the panel.Member 200 also has a dropped center portion 203 which is requiredbecause of the shaping of the phenolic end pieces and because of thepeculiar location of the center bus bar. It has been found mostsatisfactory to install a sheet of insulating material the entire lengthof the member 200 such that the insulating material is between themember 200 and the phenolic end pieces shown as 230. A sheet of mylarhas been used, but any other material is deemed to be satisfactory aslong as it will conform to the shape of the backing member 200, and yetpro vide the insulation required. Phenolic end piece 230 is fastened bytwo bolts 231 and 232 to member 200. Member 200 is fastened to the bodymember by the passage of four mounting bolts similar to that shown as21, through holes such as shown as 204 and 205 respectively. Theconnection is es sentially the same as that shown in FIG. 1, i.e. stopnut 23 is threaded onto bolt 21 until the member 200 is located at adesired distance from the rear face of the body member 10, at which timea wing nut such as the one shown as 32 in FIG. I is tightened againstthe forward face of member 200 to permanently locate the body 200 withrespect to the rear face of panel 10. The bus bars shown as 235, 236,237 are attached to the phenolic end pieces in a similar manner to thoseattached in FIG. I, and it will be noted that again the center bus bar236 is displaced rearwardly suitable distance from the bus bars 235 and237.

Attached to bus bar 235 by two bolts 238 and .239 is a heavy gauge busadapter 240. Bus adapter is rigidly joined to bus bar 235 in order toensure good electrical contact, and two holes 241 and 242 which aredrilled and tapped completely through the right-hand portion of busadapter 240. Similarly a U- shaped bus adapter 243 is attachedelectrically to bus bar 236 by means of the two bolts shown in the bightof U-shaped member 243. Similarly member 244 is attached to bus bar 237by means of the two bolts shown. It will be-noted that the bus adapters238, 243 and 244 i are provided with two spaced t'apped'holes similar tothose shown as 241 and 242 in member 238. The faces of the members 238,243 and 244 which are located in the central portion of the bus barassembly immediately in front of bus bar 236, are all in the samevertical plane. This is absolutely necessary for the attachment of acircuit breaker of the type shown as 245. A clearance hole 246 isprovided in circuit breaker 245 for the passage of bolt 247 through thehole 24, into the tapped hole 248 provided in flange portion 202 of thesteel sheet member 200. The opposite end of the circuit breaker isattached to the three members 238, 243 and 244 by means of three screwssimilar to that shown as 249, which passes through energizing terminal250 of circuit breaker 245. into hole 241 which is drilled and tappedcompletely through member 238. Similarly two bolts similar to that shownas 239 are passed through the other two energizing terminals shown below250 of circuit breaker 245 into the left hand portion of member 243 andthe left hand hole of member 244. This provides a rigid attachment ofthe circuit breaker assembly to both the backing plate 200 as well asthe bus bar assembly.

FIG. 9 shows a similar circuit breaker bus bar assembly as thatdescribed in FIG. 8, with the exception that the bus bar assembly hasbeen shortened to allow for the insertion of circuit breaker in thelower portion to provide overall protection for the whole bus barassembly. The panel member 210, (similar to that shown in FIG. 1 as 10)is arranged to'have steel backing member 300 (similar to that shown as200 in FIG. 8) mounted at a specified distance from the rear face ofmember 210. Located on member 300 is a phenolic end piece 301 which isbolted by means of bolts 302 and 303 to the member 300. Phenolic endpiece 301 is quite similar to end piece 30 shown in FIG. 1, with theexception that the lower legs of member 30 have been removed. End piece301 provides provision for the center bus bar to be located behind thetwo outside bus bars. Circuit breaker 304 is thus mounted on member 300by means of bolts 305 and 306 respectively. The

' attachment of the trim member is exactly the same as statedpreviously. Four posts are provided from the rear face of panel member210 similar to those shown as 12, 13, 14 and 54, panel 10 in FIG. 1. Thetrim panel is then fastened by four bolts similar to that shown as 307to. the main body member 210.

It is quite obvious therefore, that the bus bar structure as shown inFIG. 1, is by its nature adaptable for reception of circuit breakers ofa various size. It is also seen that the main panel assembly is capableof performing various functions in spaced parallel relationship betweena pair of insulating supporting members, the center bus bar beingmounted so as to be slightly displaced from the plane which passesthrough the two outside bus bars, each of the bus bars having a seriesof tapped holes periodically located along its length, said center busbar having a segmented insulator mounted thereon and extendingsubstantially the length of said bus bar, a fastening means attached toeach of the outside bus bars and extending substantially the length ofsaid bus bar,

c. a plurality of circuit breakers mounted on said bus bar structure,said circuit breakers being arranged to form two columns consisting of aplurality of circuit breakers mounted in side-by-side relationship ineach column, all of said circuit breakers being anchored to the centerbus bar segmented insulator assembly, one column of circuitbreakersbeing anchored as well to the fastening means on one of saidoutside bus bars, the other column of circuit breakers being anchored aswell to the fastening means on the other of said outside bus bars,

d. a trim member connected to said boxlike enclosure for covering saidaccess opening.

2. A panelboard comprising insulating bus bar support means, bus barmeans supported on said bus bar support means, said bus bar meanscomprising three elongated bus bars supported in a spaced generallyparallel relationship providing a center bus bar and a pair of outsidebus bars on opposite sides of said center bus bar, a pair of circuitbreakers supported in said panelboard in an end-to-end relationship atfirst ends of said circuit breakers with said first ends being disposedgenerally over said center bus bar, an insulating member over saidcenter bus bar between said center bus bar and said first ends of saidcircuit breakers, a first insulating support structure supported on afirst of said outside bus bars, a second insulating support structuresupported on the second of said outside bus bars, a first of saidcircuit breakers at the second end thereof being supported on said firstinsulating support structure, the second of said circuit breakers at thesecond end thereof being supported on said second insulating supportstructure, and conducting means connecting each of said circuit breakersat the first end of each of said circuit breakers to said bus bar means.

3. A panelboard according to claim 2, a first hook part on said firstinsulating support structure, a second hook part on said secondinsulating support structure, said first circuit breaker at the secondend thereofbeing supported on said first insulating support structure ininterengagement with said first hook part, and said second circuitbreaker at the second end thereof being supported on said secondinsulating support structure in interengagement with said second hookpart.

4. A panelboard comprising insulating bus bar support means, a pluralityof elongated bus bars supported on said insulating bus bar support meansin a spaced generally parallel relationship, insulating breaker supportmeans supported on a first of said bus bars, a plurality of circuitbreakers supported on said panelboard aligned in a side-by-siderelationship forming a column of circuit breakers with the load end ofeach of said circuit breakers being supported on said insulating breakersupport means, said insulating breaker support means comprising shelfpart means and a plurality of spaced hook parts, each of said circuitbreakers at the load end thereof resting on said shelf part means andbeing in interengagement with a different one of said hook parts, andmeans supporting the line endsof said circuit. breakers on saidpanelboard and electrically connecting the line ends of said'circuitbreakers to said plurality of bus bars.

5. A panelboard comprising insulating bus bar support means, threeelongated bus bars supported on said insulating bus bar support means ina spaced generally parallel relationship providing a center bus bar anda pair of outside bus bars on opposite sides of said center bus bar,three pairs of circuit breakers supported on said panelboard in aside-by-side relationship with the two circuit breakers of each pairbeing in an end-to-end relationship at the line ends of the two circuitbreakers of each pair and with the line ends of said circuit breakersbeing disposed generally over said center bus bar, an insulating memberover said center bus bar between said center bus bar and said line endsof said circuit breakers, a first insulating support structure supportedon a first of said outside bus bars, a second insulating supportstructure supported on the second of said outside bus bars, a firstcircuit breaker of each of said three pairs being supported at the loadend thereof on said first insulating support structure, the secondcircuit breaker of each of said three pairs being supported at the loadend thereof on said second insulating support structure, said sixcircuit breakers at the line ends thereof being supported over saidinsulating member, a first conducting means electrically connecting theline ends of a first pair of said pairs of circuit breakers to saidfirst outside bus bar, a second conducting means electrically connectingthe line ends of a second pair of said pairs of circuit breakers to saidcenter bus bar, and a third conducting means electrically connecting theline ends of the third pair of said pairs of circuit breakers to saidsecond outside bus bar.

6. A panelboard according to claim 5, said insulating member over saidcenter bus bar comprising insulating means insulating adjacentconducting means of said first second and third conducting means fromeach other.

7. A panelboard according to claim 5, three hook parts on said firstinsulating support structure, three hook parts on said second insulatingsupport structure, and each of the circuit breakers of said three pairsof circuit breakers at the load end thereof being in interengagementwith a different one of said hook parts.

8. A panelboard comprising insulating bus bar support means, a pluralityof elongated bus bars supported on said insulating bus bar support meansin a spaced generally parallel relationship, a first insulating breakersupport means supported on a first of said bus bars, a second insulatingbreaker support means supported on a second of said bus bars, a firstplurality of circuit breakers supported on said panelboard in aside-by-side relationship forming a first column of circuit breakerswith the load end of each of said circuit breakers in said first columnbeing supported on said first insulating breaker support means, a secondplurality of circuit breakers supported on said panelboard in aside-by-side relationship forming a second column of circuit breakersgenerally parallel with said first column of circuit breakers and withthe load end of each of said circuit breakers of said second columnbeing sup orted on said second insulating breaker support means, anmeans supporting the line ends of said circuit breakers of said firstand second columns on said panelboard and electrically connecting theline ends of said circuit breakers of said first and second columns tosaid plurality of bus bars.

9. A panelboard according to claim 8, each of said first and secondinsulating breaker support means comprising shelf part means and aplurality of spaced hook parts, each circuit breaker in each of saidfirst and second columns resting at the load end thereof on theassociated shelf part means and being in interengagement with adifferent one of the plurality of hook parts of the associatedinsulating breaker support means.

10. A panelboard according to claim 8, said plurality of elongated busbars comprising a third bus bar supported on said insulating supportmeans generally between said first and second bus bars and beinggenerally parallel with said first and second bus bars, insulatingbarrier means covering said third bus bar, said first and 7 secondcolumns of circuit breakers being in an adjacent end-to-end relationshipwith the line ends thereof being adjacent each other in proximity tosaid third bus bar and said insulating barrier means and with the loadends thereof being supported on said first and second insulating breakersupport means, conducting means at said line ends of said circuitbreakers connecting said circuit breakers to selected ones of saidplurality of bus bars, said circuit breakers in said first and secondcolumns being in pairs with each pair comprising a breaker in the firstcolumn and a breaker in the second column with each pair beingelectrically connected to the same bus bar, and said insulating barriermeans comprising an insulating barrier between each pair of circuitbreakers and any adjacent pair of circuit breakers.

11. A panelboard according to claim 10, each of said first and secondinsulating breaker support means comprising shelf part means and aplurality of spaced hook parts, and each of said circuit breakers at theload end thereof resting on the associated shelf part means and being ininterengagement with a different meet the hook parts of the associatedinsulating breaker support means.

12. A panelboard according to claim 11, a separate conducting means foreach of said pairs of circuit breakers, a first of said conducting meansconnecting the first pair of said pairs of circuit breakers to saidfirst bus bar, a second of said conducting means connecting a secondpair of said pairs of circuit breakers to said second bus bar, and athird of said conducting means connecting a third pair of said pairs ofcircuit breakers to said third bus bar.

1. A panelboard assembly comprising: a. a boxlike enclosure having anaccess opening therein, b. a bus bar structure mounted in said boxlikeenclosure, said bus bar structure comprising three bus bars mounted inspaced parallel relationship between a pair of insulating supportingmembers, the center bus bar being mounted so as to be slightly displacedfrom the plane which passes through the two outside bus bars, each ofthe bus bars having a series of tapped holes periodically located alongits length, said center bus bar having a segmented insulator mountedthereon and extending substantially the length of said bus bar, afastening means attached to each of the outside bus bars and extendingsubstantially the length of said bus bar, c. a plurality of circuitbreakers mounted on said bus bar structure, said circuit breakers beingarranged to form two columns consisting of a plurality of circuitbreakers mounted in side-by-side relationship in each column, all ofsaid circuit breakers being anchored to the center bus bar segmentedinsulator assembly, one column of circuit breakers being anchored aswell to the fastening means on one of said outside bus bars, the othercolumn of circuit breakers being anchored as well to the fastening meanson the other of said outside bus bars, d. a trim member connected tosaid boxlike enclosure for covering said access opening.
 2. A panelboardcomprising insulating bus bar support means, bus bar means supported onsaid bus bar support means, said bus bar means comprising threeelongated bus bars supported in a spaced generally parallel relationshipproviding a center bus bar and a pair of outside bus bars on oppositesides of said center bus bar, a pair of circuit breakers supported insaid panelboard in an end-to-end relationship at first ends of saidcircuit breakers with said first ends being disposed generally over saidcenter bus bar, an insulating member over said center bus bar betweensaid center bus bar and said first ends of said circuit breakers, afirst insulating support structure supported on a first of said outsidebus bars, a second insulating support structure supported on the secondof said outside bus bars, a first of said circuit breakers at the secondend thereof being supported on said first insulating support structure,the second of said circuit breakers at the second end thereof beingsupported on said second insulating support structure, and conductingmeans connecting each of said circuit breakers at the first end of eachof said circuit breakers to said bus bar means.
 3. A panelboardaccording to claim 2, a first hook part on said first insulating supportstructure, a second hook part on said second insulating supportstructure, said first circuit breaker at the second end thereof beingsupported on said first insulating support structure in interengagementwith said first hook part, and said second circuit breaker at the secondend thereof being supported on said second insulating support structurein interengagement with said second hook part.
 4. A panelboardcomprising insulating bus bar support means, a plurality of elongatedbus bars supported on said insulating bus bar support means in a spacedgenerally parallel relationship, insulating breaker support meanssupported on a first of said bus bars, a plurality of circuit breakerssupported on said panelboard aligned in a side-by-side relationshipforming a column of circuit breakers with the load end of each of saidcircuit breakers being supported on said insulating breaker supportmeans, said insulating breaker support means comprising shelf part meansaNd a plurality of spaced hook parts, each of said circuit breakers atthe load end thereof resting on said shelf part means and being ininterengagement with a different one of said hook parts, and meanssupporting the line ends of said circuit breakers on said panelboard andelectrically connecting the line ends of said circuit breakers to saidplurality of bus bars.
 5. A panelboard comprising insulating bus barsupport means, three elongated bus bars supported on said insulating busbar support means in a spaced generally parallel relationship providinga center bus bar and a pair of outside bus bars on opposite sides ofsaid center bus bar, three pairs of circuit breakers supported on saidpanelboard in a side-by-side relationship with the two circuit breakersof each pair being in an end-to-end relationship at the line ends of thetwo circuit breakers of each pair and with the line ends of said circuitbreakers being disposed generally over said center bus bar, aninsulating member over said center bus bar between said center bus barand said line ends of said circuit breakers, a first insulating supportstructure supported on a first of said outside bus bars, a secondinsulating support structure supported on the second of said outside busbars, a first circuit breaker of each of said three pairs beingsupported at the load end thereof on said first insulating supportstructure, the second circuit breaker of each of said three pairs beingsupported at the load end thereof on said second insulating supportstructure, said six circuit breakers at the line ends thereof beingsupported over said insulating member, a first conducting meanselectrically connecting the line ends of a first pair of said pairs ofcircuit breakers to said first outside bus bar, a second conductingmeans electrically connecting the line ends of a second pair of saidpairs of circuit breakers to said center bus bar, and a third conductingmeans electrically connecting the line ends of the third pair of saidpairs of circuit breakers to said second outside bus bar.
 6. Apanelboard according to claim 5, said insulating member over said centerbus bar comprising insulating means insulating adjacent conducting meansof said first second and third conducting means from each other.
 7. Apanelboard according to claim 5, three hook parts on said firstinsulating support structure, three hook parts on said second insulatingsupport structure, and each of the circuit breakers of said three pairsof circuit breakers at the load end thereof being in interengagementwith a different one of said hook parts.
 8. A panelboard comprisinginsulating bus bar support means, a plurality of elongated bus barssupported on said insulating bus bar support means in a spaced generallyparallel relationship, a first insulating breaker support meanssupported on a first of said bus bars, a second insulating breakersupport means supported on a second of said bus bars, a first pluralityof circuit breakers supported on said panelboard in a side-by-siderelationship forming a first column of circuit breakers with the loadend of each of said circuit breakers in said first column beingsupported on said first insulating breaker support means, a secondplurality of circuit breakers supported on said panelboard in aside-by-side relationship forming a second column of circuit breakersgenerally parallel with said first column of circuit breakers and withthe load end of each of said circuit breakers of said second columnbeing supported on said second insulating breaker support means, andmeans supporting the line ends of said circuit breakers of said firstand second columns on said panelboard and electrically connecting theline ends of said circuit breakers of said first and second columns tosaid plurality of bus bars.
 9. A panelboard according to claim 8, eachof said first and second insulating breaker support means comprisingshelf part means and a plurality of spaced hook parts, each circuitbreaker in each of said first and second columns resting at the load endthereof on the associated shelf part means and being in interengagementwith a different one of the plurality of hook parts of the associatedinsulating breaker support means.
 10. A panelboard according to claim 8,said plurality of elongated bus bars comprising a third bus barsupported on said insulating support means generally between said firstand second bus bars and being generally parallel with said first andsecond bus bars, insulating barrier means covering said third bus bar,said first and second columns of circuit breakers being in an adjacentend-to-end relationship with the line ends thereof being adjacent eachother in proximity to said third bus bar and said insulating barriermeans and with the load ends thereof being supported on said first andsecond insulating breaker support means, conducting means at said lineends of said circuit breakers connecting said circuit breakers toselected ones of said plurality of bus bars, said circuit breakers insaid first and second columns being in pairs with each pair comprising abreaker in the first column and a breaker in the second column with eachpair being electrically connected to the same bus bar, and saidinsulating barrier means comprising an insulating barrier between eachpair of circuit breakers and any adjacent pair of circuit breakers. 11.A panelboard according to claim 10, each of said first and secondinsulating breaker support means comprising shelf part means and aplurality of spaced hook parts, and each of said circuit breakers at theload end thereof resting on the associated shelf part means and being ininterengagement with a different one of the hook parts of the associatedinsulating breaker support means.
 12. A panelboard according to claim11, a separate conducting means for each of said pairs of circuitbreakers, a first of said conducting means connecting the first pair ofsaid pairs of circuit breakers to said first bus bar, a second of saidconducting means connecting a second pair of said pairs of circuitbreakers to said second bus bar, and a third of said conducting meansconnecting a third pair of said pairs of circuit breakers to said thirdbus bar.